Marsh vegetation in the Mino-Mikawa region of Aichi pref., the western part of Shizuoka pref. and the southeastern part of Gifu pref. was examined by Braun-Blanquet's phytosociological method, and compared with similar associations reported from the western parts of Japan. Marsh vegetation in this region is characterized by genus Utricularia, Eriocaulon, and Rhynchospora, and the differentiation of communities is influenced mainly by topographical and stratigraphical features and formative processes of marshes. The vegetation was divided into six communities : 1. Eriocauletum nudicuspis ; 2. Rhynchosporetum chinensis ; 3. Eriocaulon mikawanum community ; 4. Eriocaulon buergerianum community ; 5. Sclerietum rugosae, ass. nov. ; 6. Metanarthecium luteo-viride - Moliniopsis japonica community. These communities are included in the alliance Eriocaulo-Rhynchosporion fujitani. The Sclerietum rugosae was described as a new association in this study. It is characterized by Scleria rugosa var. glabrescens, Scleria rugosa var. rugosa, Drosera spathulata, and Lycopodium cernuum, and is distributed in the Mino-Mikawa region and in low elevations from Kinki to Chugoku district.